Antero Reservoir
Park County, Colorado3,446 acresView mapDirections
Nutrients and algae sit mid-range for this region.
↓ down from B at the last regrade
- Oligotrophic
- #1 of 2 in the county
- 112 ft max depth
- Limited data
Antero Reservoir in Park County, Colorado has a water quality grade of C (Fair). Water clarity: 14.8 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 3446 acres.
- Clarity
- 14.8 ft
- Max depth
- ~112 ft est.
- Area
- 3,446 acres
- Type
- Oligotrophic
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Watch Antero Reservoir’s letter
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Antero Reservoir is a 3,446-acre cold, clear oligotrophic lake in Park County, Colorado with an estimated average depth of about 112 feet. Water quality is graded C based on 3 sampling years through 2021. Compared to the 1 other monitored lakes in Park County, Antero Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2021-09-23. Grade methodology: LakeQuality methodology.
What Antero Reservoir is good for
From access and monitoring records, not editorial picks.
- Clear water14.8 ft of visibility
- Big water3,446 acres
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Good clarity, visible to about 14.8 ft. Phosphorus 15 µg/L. Chlorophyll-a 1.1 µg/L. TSI 38. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.8 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 1.1 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~112 ft est. |
| Average Depth | ~51 ft est. |
| Surface Area | 3,446 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Antero Reservoir.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Antero Reservoir
Reservoir Info (USACE NID)
Antero Reservoir is a man-made reservoir impounded by the Antero (completed 1909), built primarily for water supply on the S. Fork S. Platte River; earth-type dam, 48 ft tall and 4,190 ft long.
- Surface area
- 3,446 ac
- Normal storage
- 44,733 ac-ft
- Max storage
- 92,651 ac-ft
- Drainage area
- 200 sq mi
- Hazard class
- High
- Owner
- DENVER BOARD OF WATER COMMISSIONERS
All listed purposes: Water Supply;Recreation.
Source: USACE National Inventory of Dams, NID ID CO00351 · Operator website
County Ranking
Ranked #1 of 2 lakes in Park County
Nearby Lakes in Park County
Frequently asked questions about Antero Reservoir
Where is Antero Reservoir?
- Antero Reservoir is a lake in Park County, Colorado. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Antero Reservoir?
- Antero Reservoir in Park County, Colorado has a water quality grade of C (Fair). Water clarity: 14.8 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 3446 acres.
Is Antero Reservoir safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Antero Reservoir?
- No published bathymetric survey covers Antero Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 112 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 3446 acres.
Explore Antero Reservoir across LakeQuality
4 thermal springs within 22.4 mi, nearest Hartsel Hot Springs
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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Other Grade C Lakes in Colorado
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Where this data comes from
16 measurements from 2 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX16 samples · 2021
Analytical methods
- Secchi disk depth measurement
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrogen in Water by Pyrolysis Detection
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)